A defended enclosure or hillfort at the top of the north-facing slope above Nant Tarthwynni. It is depicted on modern Ordnance Survey mapping as an oval hillslope enclosure, about 75m in diameter, defined by the vestiges of a bank and ditch with an east-facing, downslope entrance, having a roughly concentric bank and ditch about its southern perimeter. The southern three-quarters of the hillfort now lie within a forestry plantation, the boundary of which reflects the former boundary shown on the late 19th century Ordnance Survey maps. The northern quarter lies on the open common, the ground surface falling away steeply to the north down to the Nant Tarthwynni. Possibly because the ground is so steep the defences on this northern side were not pronounced. The eastern part is defined by a terraced cut with no obvious bank or ditch, the western part has a small bank on the top of the terraced cut. As the bank turns towards the south it becomes more pronounced. Vegetation cover in July 2008 was grass. The rain gauge shown on modern Ordnance Survey maps was not present.

RCAHMW, 28th June 2010